Reaction motor fuels



United States Patent ()fi ice 3,6583% Patented Got. 16, 1962 3,058,301 REACTION MOTOR FUELS Olaf E. Larsen, Bartlesville, Stalin, and Eugene D. Guth, Idaho Falls, Idaho, assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Dec. 24, 1958, Ser. No. 782,977 20 Claims. ((31. oil-35.4)

This invention relates to reaction motor fuels. In one aspect this invention relates to reaction motor fuels suitable for use in reaction motors such as rocket motors, ram jet motors, and the like. In another aspect this invention relates to a method of operating a reaction motor using said new reaction motor fuels.

Rocket motors are operated by burning a mixture of fuel and oxidant in a combustion chamber and causing the resulting gases to be expelled through a nozzle at high velocity. Liquid propellants are frequently preferred over solid propellants where it is necessary to vary thrust during flight. Liquid propellants can be classified as bipropellants and as monopropellants and the latter are either a single compound or mixtures of compounds. The principal elements of a rocket motor utilizing a liquid fuel comprise a combustion chamber, exhaust nozzle, an injection system, and propellant control valves. The propellant gases are produced in the combustion chamber at pressures governed by the chemical characteristics of the propellant, its rate of combustion, and the cross-sectional area of the nozzle throat. The gases are ejected into the atmosphere through the nozzle with supersonic velocity. The function of the nozzle is to convert the pressure of the propellant gases into kinetic energy. The reaction of the discharge of the propellant gases constitutes the thrust developed by the rocket motor.

An object of this invention is to provide a new reaction motor fuel. Another object of this invention is to provide a new reaction motor fuel by employing a suitable emulsifying agent to stabilize an emulsion of an amine nitrate, a liquid hydrocarbon fuel, and nitric acid. Another object of this invention is to provide a new reaction motor fuel which is suitable for use in a reaction motor such as a rocket motor, a ram jet motor, or the like, for developing thrust. Another object of this invention is to provide a method for operating a reaction motor such as a rocket motor, a ram jet motor, using the reaction motor fuels of the inventin. Other aspects, objects, and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus according to the invention there is provided a fuel composition suitable for use in a reaction motor, comprising, as a stable emulsion, a mixture of (1) from to 60 weight percent of a normally liquid hydrocarbon fuel, (2) from 5 to 50 weight percent of a nitric acid oxidizer containing at least about 70 weight percent of HNO;;, (3) from 25 to 60 weight percent of an amine nitrate, and (4) from 1 to weight percent of an emulsifying agent which is chemically non-reactive under the conditions of mixing and storage, i.e., until ignition is effected, with said acid and which is capable of stabilizing an emulsion of said components (1), (2), and (3).

Further according to the invention there is provided a method of operating a reaction motor which comprises the steps of injecting into the combustion chamber of said motor one of the fuel compositions of the invention, igniting and burning said fuel composition, and exhausting gaseous products of combustion from said motor.

As indicated above the reaction motor fuel compositions of the invention comprise an emulsified, non-hypergolic mixture of four components. Mutual compatability of said components is achieved through the effect of the emulsifying agent. The reaction motor fuels of the invention are particularly suitable for use in ram jet engines. They can be formulated so that oxygen from the air is required for complete combustion and such fuels find ready use in a ram jet engine. For example, fuels containing less than the stoichiometric amount of oxidizer, and which thus require oxygen from the air for complete combustion, can be used in a ram jet motor in the initial phase of operation, e.g., until the ram jet has attained a speed at which sufficient air is available for complete combustion. With complete combustion there is an increase in efiiciency of operation. It is thus possible to provide a fuel composition containing a higher percentage of fuel component and a lower percentage of oxidizer component which will be more efficient at normal operating speeds of the ram jet.

However, fuel compositions containing a stoichiometric amount of oxidizer, as well as oxidizer-rich fuel compositions, can also be prepared. Said fuel compositions of the invention containing a stoichiometric amount of oxidizer, and said oxidizer-rich fuel compositions, are, as will be recognized by those skilled in the art, monopropellants, and are suitable for use in rocket motors wherein all of the oxygen necessary for combustion must be injected into the combustion chamber. In those fuel compositions of the invention containing a stoichiometric amount of oxidizer, said stoichiometric amount of oxidizer is defined as the amount required to obtain complete combustion to nitrogen, carbon dioxide, and water. In computing said stoichiometric amount of oxidizer consideration is given to the amount of emulsifying agent which is used to emulsify the mixture of amine nitrate, liquid hydrocarbon fuel, and nitric acid oxidizer. Thus, the stoichiometric amount of oxidizer includes the amount necessary to oxidize said emulsifying agent as well as the amount necessary to oxidize the liquid hydrocarbon and the amine nitrate with which the nitric acid is emulsified. A slightly fuel-rich mixture is usually required to give an optimum rocket motor performance.

In the operation of a reaction motor using the fuel compositions of the invention, said fuel composition can be injected into the combustion chamber of said motor in any suitable manner known to those skilled in the art. After injection into said combustion chamber the fuel composition can be ignited by any suitable means such as, for example, by an electric igniter.

Suitable amine nitrates for use in the practice of the invention include those selected from the group consisting of piperidine nitrate, p ufidine nitrate, Z-methylpyridine nitrate, and amine nitrates characterized by a formula selected from the group consisting of 1 R1lTT'HNOs and Ra\ R2 N-R3-N/ (HNCEI) n R2 R2 wherein: n is an integer of from 1 to 5; each R and each R is selected from the group consisting of acyclic, alicyclic, and aromatic hydrocarbon radicals containing from 1 to 8 carbon atoms, and hydrogen, at least one R being one of said hydrocarbon radicals; and R is selected from the group consisting of (a) alkylene, alkenylene, and alkynylene hydrocarbon radicals containing from 2 to 8 carbon atoms wherein the carbon atoms attached to the nitrogen atoms are attached to adjoining carbon atoms by single valence bonds, and

(b) {R X} .,R radicals wherein each R is an alkyl 3 ene radical containing from 2 to 4 carbon atoms, and X is selected from the group consisting of oxygen, sulfur, and

radicals wherein R is as defined above, y is an integer of from 1 to 3, and z is an integer of from 1 to 3;

Methylamine nitrate Dimethylamine nitrate Trimethylamine nitrate Ethylamine nitrate Diethylamine nitrate Triethylamine nitrate Propylamine nitrate Dipropylamine nitrate Tripropylamine nitrate Isopropylamine nitrate Tertiary butylamine nitrate Isobutylamine nitrate Cyclopentylamine nitrate Cyclohexylamine nitrate Cyclooctylamine nitrate Dicyclohexylamine nitrate Tricyclohexylamine nitrate 4-cyclohexenylamine nitrate Phenylamine nitrate Diphenylamine nitrate Tri-n-butylamine nitrate N,N-di-n-octyl-p-tolylamine nitrate o-Methylbenzylamine nitrate N,N,N,N-tetramethylethane-1,2-diamine dinitrate N,N,N',N-tetraethylethane-1,2-diamine dinitrate N,N,N,N'-tetra-n-octylethane-1,2-diamine dinitrate N,N,N,N'-tetramethylpropane-1,2-diamine dinitrate N,N,N,N'-tetramethylpropane-1,B-diamine dinitrate N,N,N,N'-tetraethylpropane-1,3-diamine dinitrate N,N,N',N'-tetrabutylpropane-1,3-diamine dinitrate N,N,N,N'-tetrahexylpropane-l,3-diamine dinitrate N,N,N',N'-tetramethylbutane-l,4-dia1nine dinitrate N,N,N,N-tetracyclohexylbutane-1,4-diamine dinitrate N,N,N,N'-tetraphenylbutane-1,4-diamine dinitrate N,N,N',N'-tetraphenyl-n-3-octene-1,3-diamine dinitrate N,N,N,N'-tetracyclohexylhexane-2,6-diamine dinitrate N,N,N',N-tetramethyl-Z-butene-1,4-diarnine dinitrate N,N,N,N-tetramethyl-Z-butyne-1,4-diamine dinitrate N,N,N,N-tetramethyloctene-4,8-diamine dinitrate N-phenyl-N-n-octylethane-1,2-diamine dinitrate N,N,N,N'-tetra-n-octyloctane-1,Z-diamine dinitrate N,N-di(2-ethylhexyl) 2-butene-1,4-diarnine dinitrate N,N,N',N-tetraethy1-4-octyne-1,8-diamine dinitrate Bis-(N,N-dimethylaminoethyl) ether dinitrate Bis-(N,N-di-n-octylamino-n-butyl)ether dinitrate N-cyclohexylaminopropyl N-phenylaminopropyl ether dinitrate N-Z-ethylphenylaminoethyl amino-n-butyl ether dinitrate Bis(amino-n-butyl) ether dinitrate Bis N,N-di-2-ethylcyclohexylamino-n-bu tyl thioether dinitrate Bis(aminoethyl)thioether dinitrate Bis(N-N-dimethylaminoethyl) thioether dinitrate N,N,N',N'-tetramethyl-l,3-diamine-2-propanol dinitrate N,N,N,N'-tetraethyl-1,9-dian1ino-5-nonanol dinitrate N,N',N'-tri-2-ethylcyclohexyl-l,4-diamino-2-butanol dinitrate N,N,N',N,N"-pentamethyldiethylenetriamine trinitrate N,N,N"-tricyclohexyldiethylenetriamine dinitrate 4 N,N,N'-tri-n-octyldiethylenetriamine trinitrate N,N,N',N',N,N"-hexamethylpropane-1,2,3-triamine trinitrate N ,N ,N ,N ,N ,N ,N ,N ,N ,N -decamethylpentane- 1,2,3,4,5-pentane pentanitrate N ,N ,N ,N ,N -pentaethyltetraethylenepentamine pentanitrate N-ethyl-Z-butynylamine nitrate N-methyl-Z-butynylamine nitrate Di(2-butynyl) amine nitrate N-hexyl-Z-propynylamine nitrate N-propyl-3-hexynylamine mtrate The preferred compounds are the nitrates of primary, secondary, and tertiary mono-amines and tertiary diamines. For these preferred compounds the preferred hydrocarbon R groups are alkyl groups having 1 to 6, inclusive, carbon atoms. For the tertiary diamines, the preferred R groups are alkylene groups having 3 to 6 carbon atoms. These preferred compounds generally have a greater stability in the acid solution. Presently more preferred amine nitrates for use in the practice of the invention include the following:

Piperidine nitrate Pyridine nitrate N,N,N',N-tetramethylethane-1,2-diamine dinitrate N,N,N,N'-tetramethylpropane-1,2-diamine dinitrate N,N,N,N-tetramethylpropane-1,3-diamine dinitrate N,N,N,N'-tetramethylbutane-l,3-diamine dinitrate Methylamine nitrate Dimethylamine nitrate Triethylamine nitrate Trihexylamine nitrate Amine nitrates can be prepared by several methods. One method is to react an amine with nitric acid. Another method which can be employed is to form a salt of the amine, such as a hydrochloride or an acetate, and then react said amine salt with nitric acid. It is also known that amine nitrates can be prepared from amines or amine salts by ion exchange processes. For example, a solution of the amine in a suitable solvent can be contacted with an ion exchange resin which has been previously regenerated by washing the resin with a solution containing the desired anion, e.g., with nitric acid solutions. Further details regarding the preparation of amine nitrates are given in Example I below.

Any suitable emulsifying agent which is chemically non-reactive With nitric acid under the conditions of mixing and storage, i.e., until ignition is effected, and which is capable of stabilizing an emulsion of a liquid hydrocarbon, nitric acid, and an amine nitrate, can be used in the practice of the invention. Examples of suitable emulsifying agents which can be used in the preparation of the rocket fuel compositions of the invention include, among others, the following: (A) Derivatives of imidazoline, also called glyoxaldine, having the structure where R is an alkyl or alkenyl radical containing from 12 to 18 carbon atoms, and R is OH or NH Examples of R are dodecyl, tetradecyl, hexadeceneyl, heptadecyl, octadecyl, 4-propyl-decyl, and heptadeceneyl radicals. Specific compounds include: l-hydroxyethyl-Z-heptadecenyl glyoxaldine (Amine 220), l-aminoethyl-Z-heptadecyl glyoxaldine, l-hydroxyethyl-Z-dodecyl glyoxaldine, and l-hydroxyethyl-2-octadecyl glyoxaldine; (B) sulfated fatty oils, i.e., esters of glycerol and a 6 to 18 carbon atom aliphatic fatty acid which is sulfated so as to contain sulfated groups or sulfonated so as to contain sulfonated groups in the acid chain, such as: trihexyl sulfotricarbyllate (Nekal NS), castor oil sulfonate (Turkey red Oil).

'sulfonated tallow (Napco 1497B); (C) aliphatic fatty acid amides which contain from 12 to 18 carbon atoms, such as: dodecanamide, stearamide, oleamide, and hexadecanamide; (D) the condensation products of nonyl phenol with from 4 to 8 mols of ethylene oxide such as Igepal CO-430, and representing the condensation product obtained when 4 zmols of ethylene oxide are condensed with one mol of nonyl phenol; (E) N-alkyl trimethylenediamines having alkyl groups with from 12 to 18 carbon atoms such as: N-dodecyl trimethylenediamine, N-heptadecyl trimethylenediamine, and N-octadecyl trimethylenediarnine; and (F) copolymers formed by copolymerizing a predominantly non-polar alkyl acrylate monomer with an aminoalkyl acrylate monomer which contains a basic nitrogen atom. Particularly suitable copolymers are those formed by copolymerizing, in parts by weight per 100 parts of monomers, from 5 to 50 parts of at least one monomer selected from the group of alkyl acrylate esters having the formula R 0 I ll H2O: C-ORs with from 95 to 50 parts of at least one monomer selected from the group consisting of aminoalkyl acrylates having the formula wherein each R is selected from the group consisting of hydrogen, and alkyl radicals containing from 1 to 3 carbon atoms; each R is an alkyl radical containing from to 18 carbon atoms; each R is an alkylene radical containing from 1 to 8 carbon atoms; and each R is selected from the group consisting of hydrogen, and alkyl radicals containing from 1 to 18 carbon atoms.

Suitable predominantly non-polar alkyl acrylate monomers for use in the practice of the invention include, among others, those given in Table I below:

TABLE I Alkyl Acrylate Monomers Rio TABLE II Aminoalkyl acrylates Aminomethyl acrylate Aminomethyl methacrylate Aminopentyl methacrylate Aminopropyl methacrylate Aminopentyl acrylate Aminohexyl methacrylate Aminoheptyl methacrylate Aminooctyl methacrylate Aminomethyl ethacrylate Aminomethyl propacrylate Aminohexyl ethacrylate Aminooctyl ethacrylate Amino-2-ethylhexyl acrylate Dimethylaminomethyl methacrylate Diethylaminoethyl acrylate Diisopropylaminoethyl methacrylate 6 Dihexylaminoethyl methacrylate Di-(2,4,6-triethyloctyl)aminoethyl methacrylate Didodecylaminoethyl methacrylate Dioctadecylarninoethyl methacrylate Dimethylaminopropyl methacrylate Dimethylaminobutyl acrylate 1 Dimethylaminopentyl methacrylate Dimethylaminooctyl methacrylate Dihexylaminooctyl methacrylate Dihexylaminooctyl ethacrylate Dioctylaminooctyl methacrylate Dimethylamino-(2-ethylpropyl) acrylate The above-mentioned acrylate monomers can he copolymerized by any method known to those skilled in the art to form the copolymers used in the practice of the invention. Normally these copolymers are prepared by emulsion, bulk, and solution polymerization processes. For example, said monomers can be emulsified in water and a polymerization catalyst such as benzoyl peroxide added thereto. The polymerization can be effected at temperatures in the range of 20 to 150 C. until the desired degree of polymerization has been effected. The resulting copolymer can be recovered from the reaction mixture after coagulation thereof with sodium chloride. Further information regarding the details of said copolymerization can be found in US. Patents 2,138,031 and 2,138,763, issued to George D. Graves on November 29, 1938. Said monomers are preferably copolymerized in amounts, in parts by Weight per 100 parts of monomers, ranging from 5 to 50 parts of at least one of said alkyl acrylate monomers with from 95 to 50 parts of at least one of said amino alkyl acrylate monomers.

Suitable copolymers prepared from the above-described monomers and which are suitable for use in the practice of the invention include among others the following:

TABLE III Monomer Oopolymers Ratio deeyl methacrylate/aminopentyl methacrylate.

dodeeyl methacrylate/aminopentyl acrylate.

tetradecyl methacrylate/aminooctyl methacrylate. tridecyl methacrylate/aminoethyl/e thacrylate.

dodecyl ethaerylate/amino-2-ethylhexy1 acrylate. hexadeeyl ethacrylate/dioctadeeylaminoethyl methacrylate.

helxzzdecyl ethacrylate/dioctadecylaminoethyl methacrydoldgeyl propacrylateldimethylaminopropyl methacryhelxajdecyl propacrylate/dimethylaminooctyl methacrye. decyl methacrylate/dihexylaminooctyl methacrylate. dodecyl methacrylate/dimethylamino-(2ethylpropyl)acrylate. dodecyl acrylate/aminoethyl acrylate. hexadeeyl methacrylate/aminoethyl methacrylate. octadecyl ethaerylate/didodecyl aminoethyl ethaorylate. dodecyl methacrylate/diethylaminoethyl methacrylate.

dodecyl methacrylate/diethylaminoethyl methacrylate.

.The presently preferred emulsifying agents are the above-described derivatives of imidazoline and the abovedescribed acrylate polymers.

Since water tends to retard combustion, the nitric acid used in a propellant system is preferably substantially free of water. Thus, the presently most preferred oxidizer is anhydrous nitric acid. However, other more dilute nitric acids can be used in the practice of the invention. White fuming nitric acids and red fuming nitric acids of varying concentrations are available commercially, and all are useful in the practice of this invention. White fuming nitric acid usually contains about 90 to 99 Weight to about 10 weight percent water. Red fuming nitric acid usually contains about to 90 weight percent HNO from 2 to 25 weight percent N0 and up to about 10 weight percent water. Of course, mixtures of the abovedescribed acids can be employed to give an acid having any intermediate composition, and all are useful as oxidizers in the practice of this invention. Thus, it has been found that nitric acids of all types containing at least about 70 weight percent HNO are useful as oxidizers in the practice of this invention.

The reaction motor fuel compositions of the invention recovered by filtration, washed with cold acetone or ether, and dried in a vacuum desiccator at room temperature. The melting point and stability of the amine nitrate were then determined. None of the amine nitrates which were prepared were found to be shock sensitive to the blow of a can be prepared by any stutable method which Will give hammer. The results of these runs are given below in a stable emulsion of the components of said composition. Table IV.

TABLE IV Mols Percent Yield of M.P. of N itric Aqueous Mols Amine Amine Run No. Amine Charged Acid Acid (Wt. Amine Nitrate, Nitrate,

Charged Percent; Charged Percent C.

HNOs) N ,N,N ,N-tetramethylethane-1,Z-diamine 0. 606 40. 5 0. 275 96. 3 220-221 N,N,N',N-tetramethylpropane-1,2-din1nine 0. 60C 33. 4 0.275 92. 3 177-179 N,N,N,N-tetramethylbutane-1 3-diamiue 0. 606 40. 5 0. 275 95. 115-116 N,N,N,N-tctramethylbutane-1,3-diamine 1. 19 70.0 0. 578 97. 0 115-116 N,N,N,N-tetramethyl-2-butync-lA-diaminc 0. 6 41.0 0. 285 96. 4 145-146 N,N,N,N-tetraethylethane-l,2-diamine 0. 6 41. O 0. 285 76. 142-143 N,N,N,N-tetramethylbutane1,4-diamine. 0. 43 70. 0 0. 208 08. 7 173-174 N,N,N,N-tctramethylbutane-1,2-diamine. 0. 40 70.0 0. 183 94. 3 173-174 Bis( ,N-diethylarninoethyhether 0. 51 70.0 0.25 72.0 88-03 N,N,N, -tet1'amethyl-1,3-diamino-2-prop" 0.51 70.0 0.20 85.2 120-124 N,N,N,N-tetracthyl-l,3-diamino-2-propanol. 0. 51 70.0 0. 25 91. 2 113-114 N,N,NN,N"-pentamethyldiethylene triamin 0.70 70.0 0. 23 80.0 162-163 N,N,N,N,N,N-hexamethylpropane-l,2,3-triamine 0.53 70.0 0. 173 65. 3 104-106 N ,N -dimethylethylene-l,2-diamine 0.505 60.0 0. 5 enot ;l 125 cor N, N,N,N-tetramethyl-2-butene-1,4-diam ine 0. 44 70. 0 0. 21 88. 8 179-180 N,N,N,N-tetraethylpropane-1,3-diamine 0.42 70. 0 0. 2 97. 0 157. 5-159. 5

1 In this run, the amine was dissolved in an equal volume of acetone.

Herein and in the claims, unless otherwise specified, a stable emulsion is defined as one in which no appreciable phase separation occurs upon quiescent standing for a period of at least eight hours. Emulsion compositions Within the scope of the invention can be prepared having an emulsion stability ranging from eight hours to more than seven days.

A presently preferred method of preparation of the fuel compositions of this invention is to 1) add the emulsifying agent to the liquid hydrocarbon fuel to form a first solution, (2) dissolve the amine nitrate in the nitric acid so as to form a second solution, and (3) mix said first solution and said second solution to obtain a stable emulsion. Any suitable means for mixing said two solutions can be employed. Highly staisfactory results and essentially completely stable emulsions of said components have been prepared by employing conventional stirring equipment such as an impeller immersed in the liquid in conventional manner. Essentially completely stable emulsions have been prepared by stirring or shaking the two above-described solutions for as short a time as 30 seconds. It is preferred to mix said solutions under conditions at which the temperature of the resulting mixture does not exceed C. It is also preferred to store the prepared fuel compositions at reduced temperatures, e.g. below about 15 C.

The following examples will serve to further illustrate the invention.

EXAMPLE I A number of runs were made in which polyamine compounds were reacted with nitric acid to form the corresponding amine nitrates. These runs were carried out according to the following procedure.

An amount of the pure polyamine compound was charged to a flask, after which an amount of aqueous nitric acid was charged slowly to said flask by means of a dropping funnel. The temperature of the flask contents was maintained within the range of from 0 to 10 C. by means of an ice bath and by adjusting the rate of addition of the nitric acid to keep the temperature of the reaction mass below 10 C. During the addition of the nitric acid, the flask contents were stirred vigorously. After the nitric acid has been charged, the flask contents were stirred for several minutes to insure complete reaction, after which said flask contents were poured into approximately 5 times its Volume of chilled acetone (-10 to C.). The amine nitrate precipitated out. This precipitate was EXAMPLE II A fuel rich ram jet rocket fuel composition (identified as fuel A below) was prepared by mixing 11.3 parts by weight of an emulsifying .agent consisting of l-hydroxyethyl-Z-heptadecenyl glyoxalidine (Amine 220) with 9.3 parts by weight of a low volatility isoparaflinic JP-4 hydrocarbon fuel to give a first solution. A second solution was formed by dissolving 49.4 parts by weight of N,N,N',N'-tetramethylbutane-1,3-diamine dinitrate in 30.0 parts by weight of anhydrous white fuming nitric acid. Said second solution was then mixed with said first solution by stirring with a conventional stirrer for about 30-40 seconds. Upon mixing of said solutions an emulsion which was stable for more than 7 days was obtained.

A second fuel composition (identified as fuel B below) was prepared by dissolving 49.4 parts by weight of N,N,N,N'-tetramethylbutane-1,3-diamine dinitrate in 30.0 parts by weight of anhydrous White fuming nitric acid. Said second fuel B thus contained the same ratio of amine nitrate and nitric acid as said first fuel A.

A third fuel composition (identified as fuel C below) consisting of N,N,N,N-tetramethylbutane-1,3-diarnine dinitrate and anhydrous white fuming nitric acid in stoichiometric proportions was prepared by dissolving 33.8 parts by weight of said amine nitrate in 66.2 parts by weight of said acid.

Said three fuel compositions A, B, and C were then tested for burning rate by placing a portion of each in a separate 8 mm. ID. test tube. The surface of the tube contents was then ignited and the time required to burn a 2" long section of the tube contents in the presence of air at atmospheric pressure was recorded. The burning rate for each fuel composition in inches per second was then calculated. The results of said burning rate tests were as follows:

9 Typical IP-4 jet fuels are set forth in Table V given below. Fuel #2 in said table is the type used in the above examples.

TABLE V Typical JP-4 Jet Fuels Existent Gum, Mg./l ml Potential Gum, Mg./100 m1 Freezing Point, FM."

Sulfur, Total, wt Percent 0.109 0 0034. L. Heat of Comb., B.t.u/1b 16,651 19,006

es Aniline Point, F 128. Aromatics, Vol Percent 13. 2 0. 6 Bromine No 1.1 1. 4 Smoke Point, mm. 24. 5 Smoke Volatility Indexa--. 56. 8

EXAMPLE III In the absence of an emulsifying agent a stable emulsion does not result when an amine nitrate, nitric acid, and a normally liquid hydrocarbon are mixed. Three parts by weight of an amine nitrate solution in anhydrous white fuming acid consisting of 33.8 weight percent of N,N,N,N-tetramethylbutane-1,3-diamine dinitrate in 66.2 weight percent of said acid were mixed with 3.85 parts by weight of lP-4 fuel No. 2 (see Table V) to give a mixture having the following composition:

Weight percent Amine nitrate 14.7 Nitric acid 29.2 JP-4 fuel 56.1

This mixture did not produce a stable emulsion. After mixing, the mixture separated in less than one minute into two distinct layers, i.e., a hydrocarbon layer and an acid layer.

While the JP-4 jet fuels described in Table V above are of the presently preferred liquid hydrocarbon fuels for use in the practice of the invention, it is to be understood that other normally liquid hydrocarbon fuels can be used. Thus, other hydrocarbon jet fuels can also be used. Suitable normally liquid hydrocarbons which can be used in the practice of the invention include paraffin, cycloparafiin, and aromatic hydrocarbons in the C-S to 0-30 range or mixtures thereof. Examples of such hydrocarbon fuels are normal pentane, normal hexane, normal heptane, benzene, kerosene, isooctane, 2,3-dimethylbutane, diisobutylene, cyclohexene, cyclohexane, isodecane, methylcyclohexane, toluene, hexadecane, pentatricontane, gasoline, naphthas, and the like. Hydrocarbons in the O5 to 0-16 range are preferred.

Since variations and modifications of the invention can be made by those skilled in the art without departing from the scope or spirit of said invention, it is to be understood that all matter herein set forth in the above discussion is merely illustrative and does not unduly limit the invention.

We claim:

1. A fuel composition suitable for use in a reaction motor, consisting essentially of, as a stable emulsion, a mixture of (1) from 10 to 60 weight percent of a nor- 10 mally liquid hydrocarbon fuel, (2) from 5 to 50 weight percent of a nitric acid oxidizer containing at least about 70 weight percent of HNO (3) from 25 to 60 weight percent of an amine nitrate selected from the group consisting of piperidine nitrate, pyridine nitrate, Z-methylpyridine nitrate, and amine nitrates characterized by a formula selected from the group consisting of wherein: n is an integer of from 1 t0 5; each R and each R is selected from the group consisting of acyclic, alicyclic, and aromatic hydrocrbon radicals containing from 1 to 8 carbon atoms, and hydrogen, at least one R being one of said hydrocarbon radicals; and R is selected from the group consisting of (a) alkylene, alkenylene, and alkynylene hydrocarbon radicals containing from 2 to 8 carbon atoms wherein the carbon atoms attached to the nitrogen atoms are attached to adjoining carbon atoms by single valence bonds, and (b) {R X-} R radicals wherein each R is an alkylene radical containing from 2 to 4 carbon atoms,

and X is selected from the group consisting of oxygen, sulfur, and

OH R: RzN-R2 B t'r and {F radicals wherein R is as defined above, y is an integer. of from 1 to 3, and z is an integer of from 1 to 3; the total number of carbon atoms in the molecule does not exceed 40; and the total number of amino nitrogen atoms in the molecule does not exceed 5, and (4) from 1 to 20 weight percent of an emulsifying agent which is chemically non-reactive with said acid under the conditions of mixing and storage and which is capable of stabilizing an emulsion of said components (1), (2), and (3).

2. The composition of claim 1 wherein said amine nitrate is N,N,N',N'-tetramethylbutane-l,3-diamine dinitrate.

3. The nitrate is trate.

4. The nitrate is trate.

5. The composition of claim 1 wherein said amine nitrate is N,N-dimethylethane-1,2-diamine dinitrate.

6. The composition of claim 1 wherein said amine nitrate is diisopropyl amine nitrate.

7. The composition of claim 1 wherein said emulsifying agent is 1-hydroxyethyl-2-heptadecenyl glyoxalidine.

8. The composition of claim 1 wherein said emulsifying agent is an :20 dodecyl methacrylate/diethylaminoethyl methacrylate copolymer.

9. The composition of claim 1 wherein said amine nitrate is N,N,N',N'-tetramethylbutane-1,3-diamine dinitrate and said emulsifying agent is l-hydroxyethyl-Z-heptadecenyl glyoxalidine.

10. The composition of claim 1 wherein said mixture consists essentially of:

49.4 weight percent of N,N,N,N-tetramethylbutane- 1,3-diarnine dinitrate;

30:0 weight percent of anhydrous nitric acid;

9.3 weight percent of a low volatility isoparafiinic JP-4 liquid hydrocarbon fuel; and

11.3 weight percent of 1-hydroxyethyl-2-heptadecenyl glyoxalidine.

11. In the method for the development of thrust by the combustion of a fuel in the combustion chamber of a reaction motor, the steps comprising: injecting into said combustion chamber as said fuel component a stable emulcomposition of claim 1 wherein said amine N,N,N,N'-tetramethylbutane-1,4-diamine dinicomposition of claim 1 wherein said amine N,N,N',N-tetramethylbutane-1,2-diamine dinision consisting essentially of a mixture of (1) from 10 to 60 weight percent of a normally liquid hydrocarbon fuel, (2) from to 50 weight percent of a nitric acid oxidizer containing at least about 70 weight percent of HNO (3) from 25 to 60 weight percent of an amine nitrate selected from the group consisting of piperidine nitrate, pyridine nitrate, Z-methylpyridine nitrate, and amine nitrates characterized by a formula selected from the group consisting of wherein: n is an integer of from 1 to 5; each R and each R is selected from the group consisting of acyclic, alicyclic, and aromatic hydrocarbon radicals containing from 1 to 8 carbon atoms, and hydrogen, at least one R being one of said hydrocarbon radicals; and R is selected from the group consisting of (a) alkylene, alkenylene, and alkynylene hydrocarbon radicals containing from 2 to 8 carbon atoms wherein the carbon atoms attached to the nitrogen atoms are attached to adjoining carbon atoms by single valence bonds, and (b) -ER X-]- R radicals wherein each R is an alkylene radical containing from 2 to 4 carbon atoms, and X is selected from the group consisting of oxygen,

radicals wherein R is as defined above, y is an integer of from 1 to 3, and z is an integer of from 1 to 3; the total number of carbon atoms in the molecule does not exceed 40; and the total number of amino nitrogen atoms in the molecule does not exceed 5, and (4) from 1 to 20 Weight percent of an emulsifying agent which is chemically non-reactive with said acid under the conditions of mixing and storage and which is capable of stabilizing an emulsion of said components (1), (2), and 3); igniting and burning said mixture; and exhausting gaseous products of combustion from said motor.

12. The method of claim 11 wherein said amine nitrate is N,N,N,N-tetramethylbutane-1,3-diamine dinitrate.

13. The method of claim 11 wherein said amine nitrate is N,N,'N,N'-tetramethylbutane-1,4-diamine dinitrate.

14. The method of claim 11 wherein said amine nitrate is N,N,N',N'-tetramethylbutane-1,2-diamine dinitrate.

15. The method of claim 11 wherein said amine nitrate is N,N-dimethylethane-1,2-diamine dinitrate.

16. The method of claim 11 wherein said amine nitrate is diisopropyl amino nitrate.

17. The method of claim 11 wherein said emulsifying agent is 1-hydroxyethyl-Z-heptadecenyl glyoxalidine.

18. The method of claim 11 wherein said emulsifying agent is an 80:20 dodecyl methacrylate/diethylaminoethyl methacrylate copolymer.

19. The method of claim 11 wherein said amine nitrate is N,N,N',N'-tetramethylbutane-1,3-diamine dinitrate and said emulsifying agent is 1-hydroxyethyl-2-heptadecenyl glyoxalidine.

20. A fuel composition suitable for use in a reaction motor, consisting essentially of, as a stable emulsion, a mixture of (1) from to 60 weight percent of a normally liquid hydrocarbon fuel, (2) from 5 to 50 weight percent of a nitric acid oxidizer containing at least about 70 weight percent of HNO (3) from 25 to 60 weight percent of an amine nitrate selected from the group consisting of piperidine nitrate, pyridine nitrate, Z-methyl-pyridine nitrate, and amine nitrates characterized by a formula selected from the group consisting of wherein: n is an integer of from 1 to 5; each R and each R is selected from the group consisting of acyclic, alicyclic, and aromatic hydrocarbon radicals containing from 1 to 8 carbon atoms, and hydrogen, at least one R being one of said hydrocarbon radicals; and R is selected from the group consisting of (a) alkylene, alkenylene, and alkynylene hydrocarbon radicals containing from 2 to 8 carbon atoms wherein the carbon atoms attached to the nitrogen atoms are attached to adjoining carbon atoms by single valence bonds, and (b) {R -X-} R radicals wherein each R is an alkylene radical containing from 2 to 4 carbon atoms, and X is selected from the group consisting of oxygen, sulfur, and

radicals wherein R is as defined above, y is an integer of from 1 to 3, and z is an integer of from 1 to 3; the total number of carbon atoms in the molecule does not exceed 40, and the total number of amino nitrogen atoms in the molecule does not exceed 5, and (4) from 1 to 20 weight percent of an emulsifying agent which is chemically non-reactive with said acid under the condiwherein R is selected from the group consisting of alkyl and alkenyl radicals containing from 12 to 18 carbon atoms, and R is selected from the group consisting of OH and NH radicals; sulfated esters of glycerol and an aliphatic fatty acid containing from 6 to 18 carbon atoms; sulfonated esters of glycerol and an aliphatic fatty acid containing from 12 to 18 carbon atoms; aliphatic fatty acid amides containing from 12 to 18 carbon atoms; condensation products of nonyl phenol with from 4 to 8 mols of ethylene oxide; N-alkyl trimethylenediamines wherein the alkyl group contains from 12 to 18 carbon atoms; and copolymers formed by copolymerizing, in parts by weight per 100 parts of monomers, from 5 to 50 parts of at least one monomer selected from the group consisting of alkyl acrylate esters having the formula R7 0 A ll H2O: CO-RB with from to 50 parts of at least one monomer selected from the group consisting of aminoalkyl acrylates having the formula 14 Doumani et a1 July 14, 1953 Szabo et a1 Mar. 27, 1956 FOREIGN PATENTS Australia July 14, 1949 OTHER REFERENCES Cottrell et al.: Journal Chemical Society (1951), 

11. IN THE METHOD FOR THE DEVELOPMENT OF THRUST BY THE COMBUSTION OF A FUEL IN THE COMBUSTION CHAMBER OF A REACTION MOTOR, THE STEPS COMPRISING: INJECTING INTO SAID COMBUSTION CHAMBER AS SAID FUEL COMPONENT A STABLE EMULSION CONSISTING ESSENTIALLY OF A MIXTURE (1) FROM 10 TO 60 WEIGHT PERCENT OF A NORMALLY LIQUID HYDROCARBON FUEL, (2) FROM 5 TO 50 WEIGHT PERCENT OF A NITRIC ACID OXIDIZER CONTAINING AT LEAST ABOUT 70 WEIGHT PERCENT OF NHO3, (3) FROM 25 TO 60 WEIGHT PERCENT OF AN AMINE NITRATE SELECTED FROM THE GROUP CONSISTING OF PIPERIDINE NITRATE, PYRIDINE NITRATE, 2-METHYLPYRIDINE NITRATE, AND AMINE NITRATES CHARACTERIZED BY A FORMULA SELECTED FROM THE GROUP CONSISTING OF 